Killer Instinct

Lia, Cassie, and Michael drive Michael’s car to the frat party. Once there, they each use their talents to talk to different people and glean information. After a while, Cassie is approached by an arrogant male student, Geoffrey, who is a teaching assistant for Professor Fogle, the suspicious criminology teacher. He tells her that he knew Emerson because she was in his class. Cassie plays along and pretends to be interested in the case, so Geoffrey invites her to hear a lecture about serial killers. Cassie agrees, signaling to Michael to follow them.

Geoffrey takes Cassie to a lecture hall and opens up a presentation about serial killers. Before he starts, Michael comes in with a date, and they invite themselves to Geoffrey’s lecture. Geoffrey tells them about some famous serial killers, including Daniel Redding, and shows them pictures of Redding’s murder scenes. Michael then receives a message from Lia, so he and Cassie make up an excuse to leave. Before she goes, however, Cassie asks for Geoffrey’s number.

Lia, who has identified two potential witnesses, sent Michael and Cassie her location. They find her on a building’s roof with Derek and Clark, other students from Emerson’s study group. Derek is handsome and arrogant, while Clark is shy and nerdy. They reveal that Emerson and Professor Fogle were sleeping together, and Michael notices that Clark seems angry about this.

On the way home, Cassie, Lia, and Michael go over what they have learned. They conclude that both Geoffrey and Clark may be people of interest, while Professor Fogle seems like a charismatic and potentially controlling leader who has a morbid fascination with Redding. They also agree not to tell Dean about their outing or the fact that they are looking into his father.

The next morning, Sterling assigns the five teenagers some homework. Cassie and Dean find themselves reading a textbook about criminal psychology together. When they come across a chapter about “organized” and “disorganized” killers, Dean teaches Cassie about the difference between the two. Both Redding and Locke were highly organized killers, so Cassie understands that Dean is speaking from experience. Briggs and Sterling then come in to inform Dean that they need to talk with Redding, who is in prison, about Emerson’s case. Redding has agreed to help them, but he only wants to talk to Dean.

The killer speaks about their admiration for Daniel Redding and their plan to emulate him until they gain the same recognition.

Dean asks that Cassie join him, Sterling, and Briggs on a trip to the maximum-security prison where Redding is serving his sentence. Cassie offers Dean moral support before he and Briggs go to the interview room on their own. An overzealous prison guard questions Cassie’s presence and takes her and Sterling to an observation room. From behind the glass, the two of them observe part of the supposedly private conversation between Dean and his father. Redding is controlling and emotionally manipulative but eventually reveals that Fogle interviewed him for his book. He coerces Dean into sharing information about his life in exchange for information about a secluded cabin Fogle owns.

Back in the car, Sterling admits that bringing Dean to visit his father was a mistake. She also reveals that she sees a lot of herself in Cassie, which is why she is especially hard on the young girl. Sterling warns Cassie that emotions are dangerous, as they may lead Cassie to bypass FBI protocols meant to keep people from getting hurt. She also knows that Cassie left the house the previous night, but Cassie refuses to tell her anything other than the fact that Emerson and Fogle were romantically involved. As it starts getting hot in the car, Sterling takes off her jacket, and Cassie is shocked to see a brand on her collarbone just like the ones Redding put on his victims.

Noticing Cassie’s gaze, Sterling briefly explains that, while she was investigating Redding, he abducted her and held her for two days before the FBI arrested him. Briggs and Dean then return from their interview with Redding, Dean appearing tense and emotionally withdrawn. The warden has given Briggs a list of Redding’s visitors to investigate. 

Sterling tells Briggs about Emerson and Fogle’s relationship, and Briggs gets angry at Cassie for leaving the house, investigating an active case, and taking unnecessary risks. Feeling remorseful, Cassie tells him about Derek and Clark, so Briggs reveals that Redding mentioned receiving letters from one of Fogle’s students.

Once back at the house, Cassie finds Michael working on an old car in the driveway. Briggs requests everyone’s presence in the living room and then scolds the teenagers for going against orders and meddling in the investigation. The five Naturals then meet in the basement, where they update Dean on what they have found. The conversation ends with almost everyone storming away, as Dean is angry about the risks they took, Sloane is hurt that they did not include her, and Lia is upset about hurting Dean’s feelings.

Left alone with Sloane, Cassie apologizes for leaving her out of the trip to Colonial. She then goes in search of Michael, and they discuss his strained relationship with Dean. Cassie realizes that Michael, who learned to recognize anger because he grew up with an abusive father, has always felt threatened by Dean’s inner rage. Dean conceals his anger, which stems from his trauma, because he is afraid of becoming his father. Michael, however, instinctively tries to draw that anger out, which results in the two boys’ conflictual relationship. 

Sterling and Briggs then return from Fogle’s cabin, looking unhappy with their findings. Cassie deduces that Redding misled them and only revealed the location of the cabin because he knew they would find the professor dead.

The killer reminisces about killing Fogle to get rid of a loose end. They enjoyed shooting him, so they fantasize about updating their MO. However, they remind themselves that they have a plan to follow.

Director Sterling comes to the house to give the teenagers a mission. Despite Agent Sterling’s disapproval, he wants to use the Naturals to monitor Fogle’s students’ social media. He gives them Sterling’s profile of their UNSUB: a young male student, socially isolated but looking to affirm his dominance, and an organized but inexperienced killer. Cassie and the others agree to help, although they realize that they will be working within restricted parameters.

Cassie and the others wade through the social media of the hundreds of students in Fogle’s class. Cassie reverse-engineers the FBI’s profile to learn more about the crime scene and the UNSUB’s motivations. After learning that only two students, Bryce Anderson and Gary “Clark” Clarkson, took several classes with Emerson, she looks through Clark’s social media and realizes that he fits the profile.